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        [
            ["SQL SERVER","C# OOP"],
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    document.write("subject数组的长度: "+subject.length+"<br>")
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        document.write("subject数组的第"+i+"个对象是另一个数组,这个数组的长度是: "+subject[i].length+"<br>")
        for(let j=0;j<subject[i].length;j++)
        {
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